Power control with signal quality estimation for smart antenna communication systems

A method for ongoing power control for downlink communications between a communication station for transmitting a downlink signal and one or more remote receivers, the communication station including an array of antenna elements for transmitting a set of transmit signals through a set of antenna transmit apparatuses, each associated with one of the antenna elements, and a processor for spatial processing the downlink signal according to a transmit weight vector of transmit weights to form the set of transmit signals, the method comprising, for a particular remote receiver:

• (a) setting up an initial power assignment for the communication station for transmitting to the particular remote receiver using an initial transmit weight vector on a spatial channel of a conventional channel and transmitting a particular downlink signal from the communication station on the spatial channel according to the initial transmit weight vector and the initial power assignment;
• (b) receiving the particular downlink signal at the remote receiver;
• (c) estimating the quality of the received downlink signal;
• (d) determining an updated power assignment for the communication station for transmitting to the particular remote receiver, the power assignment determination using the received signal quality estimate;
• and
• (e) applying the updated power assignment at the communication station, the applying including transmitting a new downlink signal.

A method for global ongoing power control in a communication system, the communication system including a set of one or more communication stations, each communication station communicates on the uplink with a set of one or more corresponding remote transmitters and on the downlink with a set of one or more corresponding remote receivers co-located with the corresponding remote transmitters, each communication station comprising an array of receiving antenna elements, a set of receive apparatuses, each antenna element coupled to one of the receive apparatuses, a receive spatial processor, the outputs of the receive apparatuses coupled to the spatial processor for spatial processing received signals according to a receive weight vector, uplink communication with any corresponding remote transmitter being according to the receive weight vector for that remote transmitter, each communication station also including a transmit spatial processor for forming a set of transmit antenna signals according to a transmit weight vector, a set of transmit apparatuses, each transmit apparatus accepting one of the transmit antenna signals, and an array of transmitting antenna elements, each coupled to the output of one of the transmit apparatuses, downlink communication with any corresponding remote receiver being according to the transmit weight vector for that remote receiver, the method comprising:

• (a) for each communication station and for each corresponding remote transmitter of the communication station transmitting to the communication station on a spatial uplink channel of a conventional uplink channel of the communication station:
• (i) transmitting a particular uplink signal from the remote transmitter on the conventional uplink channel, the transmitting according to an initial uplink power assignment;
• (ii) determining a particular receive weight vector for communicating with the particular remote transmitter on the spatial uplink channel of the conventional uplink channel;
• (iii) receiving the particular uplink signal at the antenna elements and associated receive apparatuses as a set of received signals and spatially processing the received signals with the particular receive weight vector to form a particular received uplink signal;
• (iv) estimating the quality of the particular received uplink signal;
• (v) determining an updated uplink power assignment for the remote transmitter, the uplink power assignment determination using the received uplink signal quality estimate, the determining subject to the constraint of a predicted uplink signal quality measure being at least a target uplink signal quality;
• and
• (vi) applying the updated uplink power assignment at the particular remote transmitter, the applying including transmitting a new uplink signal, all the updated uplink power assignments in all steps (a)(v) determined as those powers that simultaneously minimizing the weighted sum of transmit powers used for transmitting to all communications stations from all of the corresponding remote transmitters, and
• (b) for each communication station and for each corresponding remote receiver of the communication station receiving from the communication station on a spatial downlink channel of a conventional downlink channel of the communication station
• (i) transmitting a particular downlink signal from the communication station to the remote transmitter on the spatial channel according to an initial transmit weight vector for the remote transmitter and according to an initial downlink power assignment;
• (ii) receiving the particular downlink signal at the remote receiver;
• (iii) estimating the quality of the received downlink signal;
• (iv) determining an updated downlink power assignment for the communication station for transmitting to the remote receiver, the downlink power assignment determination using the received downlink signal quality estimate, the determining subject to the constraint of a predicted downlink signal quality measure being at least a target downlink signal quality;
• and
• (v) applying the updated downlink power assignment at the communication station, the applying including transmitting a new downlink signal, all the updated downlink power assignments in all steps (b)(iv) determined as those powers that simultaneously minimize the weighted sum of transmit powers used for transmitting from all communications stations to all of the corresponding remote transmitters.

A method for ongoing uplink power control and receive weight vector determination for uplink communications between one or more remote transmitters and a communication station for receiving an uplink signal, the communication station including an array of antenna elements, each antenna element coupled to an associated receive apparatus, and a processor for spatial processing the outputs of the set of receive apparatuses, the spatial processing forming the uplink signal according to a receive weight vector of receive weights, the method comprising:

• for a particular remote transmitter,
• (a) determining a particular receive weight vector for communicating with the particular remote transmitter on a spatial channel of a conventional channel;
• and
• (b) separately determining a power assignment for the particular remote transmitter for transmitting to the communication station on the spatial channel.

A method for complete transmit weight vector determining for downlink communications between a communication station and one or more remote receivers for transmitting a downlink signal, the communication station including an array of antenna elements, each antenna element coupled to the output of an associated transmit apparatus, and a processor for spatial processing a downlink signal into a set of transmit signals each coupled to an input of one of the transmit apparatuses, the spatial processing forming the transmit signals according to a complete transmit weight vector, the complete transmit weight vector comprising a relative transmit weight vector of relative transmit weights and a scaling factor applied as a power assignment for use with the relative transmit weight vector, the method comprising:

• for a particular remote receiver,
• (a) determining a particular relative transmit weight vector for transmitting from the communication station to the particular remote receiver on a spatial channel of a conventional channel;
• and
• (b) separately determining a power assignment for transmitting to the particular remote receiver on the spatial channel, the power assignment forming the scaling factor to use with the particular relative transmit weight vector.